soil metagenome Targeted loci environmental

Cheatgrass (Bromus tectorum) invasion can alter community structure of arbuscular mycorrhizal fungi (AMF) in the sagebrush-steppe ecosystem. Though, the feedbacks and underlying mechanisms of a changed AMF community on sagebrush (Artemisia tridentate ssp. Wyomingensis) remain unclear. We assessed how 'own' versus 'foreign' AMF impact plant biomass, C transfer to AMF, and decomposition rates. Cheatgrass invasion changed AMF community structure and decreased AMF taxon richness. Cheatgrass biomass, sagebrush C transfer, and decomposition were not altered but sagebrush root production was reduced with 'foreign' AMF. Our results suggest that sagebrush performance declines with cheatgrass invasion due to a disadvantageous AMF community shift. 'Foreign' AMF received the same amount of C but provided less benefits to sagebrush, as shown by decreased root biomass. These findings provide insight into the feedback mechanism that can decrease native plant performance upon invasion.